Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Quantas casas são verdes?
 ###Tabelas: CREATE TABLE prize_money_won (prize_money_won_id AUTO_INCREMENT PRIMARY KEY, Player VARCHAR, Group Legs won INT, Play-Off Legs won INT, Winners Group Legs won INT, Winners Play-Off Legs won INT, Final position money won* VARCHAR, Total money won VARCHAR) CREATE TABLE european_history (european_history_id AUTO_INCREMENT PRIMARY KEY, Season VARCHAR, Round VARCHAR, Country VARCHAR, Opponent VARCHAR, Result VARCHAR) CREATE TABLE world_championship_group_d_belgium (world_championship_group_d_belgium_id AUTO_INCREMENT PRIMARY KEY, Games INT, Drawn INT, Lost INT, Points difference VARCHAR, Points INT) CREATE TABLE in_ordinary (in_ordinary_id AUTO_INCREMENT PRIMARY KEY, Date VARCHAR, Three VARCHAR, Four VARCHAR, Five VARCHAR, Seven VARCHAR) CREATE TABLE houses (houses_id AUTO_INCREMENT PRIMARY KEY, House Name VARCHAR, Composition VARCHAR, Named after VARCHAR, Founded INT, Colours VARCHAR)  
SELECT COUNT House Name FROM houses WHERE Colours = Green